Expander roll



J iy 9 s. L. HARLOW, JR 295609039 EJQANDER ROLL Filed March 5, 1949 INVTOR.

I A TTQMEM? Patented July 10, 1951 EXPANDEB ROLL Samuel L. Harlow, Jr.,

to The Firestone T Memphis, Tenn assignmire & Rubber Company, Akron, Ohio, a corporation of Ohio Application March 5, 1949, Serial No. 79,885

1 Claim. (Cl. 26-63) A primary object of the invention resides in the provision of an improved expander roll or bow bar of the type employed for example in the paper and textile arts wherein the normal wear of the roll surface area resulting from driven engagement with a continuously moving material is absorbed by an outer protecting layer detachably associated with the roll or bow bar assembly and readily replaceable, when worn, in respect thereto.

Expander rolls of the general type herein described are well known and are commonly employed by paper makers to insure maximum width of their product and to eliminate creases, wrinkles, and distortion during the manufacturing process. They are also employed by manufacturers of textiles, and especially in connec= tion with so-called plastic textiles, such for example as Velon, a trade-marked vinyl-vinylidene product manufactured by the Firestone Tire & Rubber Company of Akron, Ohio. Expanders, or how bars as they are commonly referred to, are employed in connection with the calendaring operations related to the tire building art to insure uniform and crease-free distribution of rubber or rubber-like material to the surface of textile material such as cotton or rayon to which a rubber coating has previ-= ously been applied by a known calendering method.

Bow bars are of necessity of rather expensive construction since they normally consist of a large number of individual bearing elements, usually of ball bearing construction, disposed side by side along a bowed axis about which they are free to rotate when driven by a moving prodnot which ha been directed frictionally to engage the peripheral surfaces of the various rolls comprising the assembly. It has been common practice to employ rubber or the like as a covering material for the individually mounted rolls and since the roll as a unit is frictionally driven, appreciable wear occurs which has heretofore necessitated shipping the roll as a unit to the manufacturer for complete disassembly and retreading of the individual roller units. It is impractical for the normal user to attempt to retread the rolls. Most users are remote from the locality of the manufacturer of the roll, and substantial delay and expense results from taking the roll out of service, shipping to the manufacturer for the retreadlng operation, and return. It is toward the alleviation of periodically occurring lost service use and attendant expenditures that the present invention primarily is directed.

Another object of the invention is therefore to provide an expander roll which may be continuously retained in service with an occasional recoverin operation which may be accomplished within a few minutes.

A further object of the invention is to provide a bow type expander roll with an improved work surface completely devoid of joints, crevices, and irregularities.

Other objects and advantages are generally to simplify and improve the construction of expander rolls for one or more of the purposes above stated, with special reference to the par ticular type of expander roll illustrated and de= scribed herein. Other objects and advantages will become apparent to persons skilled in the art upon an examination of the drawings, the specification, and the appended claim.

In the drawings, in which like parts are identified by the same reference numerals,

Fig. l is a perspective view of a multiple roll assembly consisting of a pair of spaced supportin rolls having an expander roll or bow bar disposed intermediate thereof in a position to ten sion material traveling between the supporting rolls;

Fig. 2 is a plan view of a roll embodying the present invention and showing part of the removable cover broken away to best illustrate the construction thereof;

Fig. 3 is a fragmentary view, partially in longitudinal section and partially in elevation, illustrating constructional details oi an improved expander roll incorporating the invention, and

Fig. 4 is a section taken along line H of Fig. 3.

Referring to Fig. 1, a roll assembly is shown which has wide applicability and may be employed for any one of the purposes above mentioned, as for example in the paper, textile, or calendering art. The assembly comprises a pair of spaced supporting brackets I0 and II finding their support for example on arms l2 and I3, fragmentarily illustrated. Brackets Ill and II provide rotational support for a pair of rolls II and I! mounted on axles I 9 and 20 in mutual parallel spaced relation. An expander roll of how bar, generically designated 22, finds its support in brackets in and l I .by means of mountings 24 and 25 intermediate rolls I 8 and I1.

Bow bar 22 i mounted with the concave side thereof directed toward roll l6. Material 30 moves continuously in the arrow direction, over roll l6 which is mounted, as above stated, freely to rotate, and under bow bar 12 which is also mounted freely to rotate as a unit in the manner described below, and over roll II, also mounted freely to rotate, to be wound on a driven roll 32 illustrated diagrammatically as being supported on a rectangular shaft 33. It is seen from this view that the material 36 engages bow bar 22 at the concave side thereof and leaves the bow bar at the convex side thereof, since the bow bar is mounted with the arc of the bow in a plane parallel to the material 30 being fed.

The construction of bow bar 22 is best shown in Fig. 3 and includes an elongate axle 35, noncircular in cross section and illustrated herein as hexagonal in cross section, axle 35 being bowed as best shown in Fig. 2 and also shown in exaggerated form in Fig. 3 for illustrative purposes. Axle 35 provides support for a plurality of roller members generically designated 36 which are retained in contiguous juxtaposition along axle 35 in clamped assembly intermediate a pair of collarlike locking elements 38 positioned at opposite ends thereof. Each roller member 36 includes an inner race element 40 complementaliy receivable over axle 35, an outer race element 42, peripherally defining a cylinder or roll, and suitable means such as balls 44 for the rotational mounting of race element 42 in respect to race element 40. It is of course obvious that any other known type of bearing, such as roller bearings, may advantageously be employed if desired, in place of the ball bearings shown.

A rubberlike covering 48 is adhesively bonded to the cylindrical peripheral surface of outer race element 42 to provide a resilient roll rotatable about axle 35. In the prior art structures surface I! constituted the work-contacting roll surface and as such required frequent replacement necessitating disassembly of the device and the individual recovering of each roll assembly. Further, since the rolls are closely spaced as shown, and since they are mounted on a curved axle, the relative angularity therebetween results in the tend ency of the rolls to present a slightly bulged or ribbed peripheral area on the concave side, considering the bow bar as a unit, while presenting a multiply creviced peripheral area on the convex side. Overlap of the resilient material 48 in respect to the outer race element 42 substantially reduces the tendency of the unit to form crevices on the convex side while accentuating the tendency to form ribs on the concave side. While this fact provided problems in prior art rolls, it presents no difliculties in the present construction wherein a unitary tube 50 of resilient material is stretched over the individual rollers to provide a readily replaceable work contacting surface 4 while protecting resilient coverings 48 from wear to thus give the immediate roll coverings an almost indefinite service life.

While the invention is not limited to the use of a particular material in the form of roll 50, it has been found that a high quality natural rubber stock, compounded for inner tube use, is admirably suited for the purpose. Roll 50 is of a normal inner diameter substantially smaller than the outside diameter of the individual roll assemblies and is stretched, for example by well known pneumatic means, to a larger diameter than that of the rolls during application. The contractile bias of roll 50 is sufficient to retain the roll in frictional engagement with the peripheral surface areas of the individual rolls and the material is suflicientlv resilient readily to absorb the axially directed expansions and contractions which will necessarily occur during the operation of the device as the tube 50 accommodates itself to constant changes in contour resulting from the revolution of the plurality of axially non-aligned individual rolls in respect to the arcuate pattern defined by axle 35.

What is claimed is:

In a device of the type described, the combination of a plurality of independently rotatable roller assemblies disposed on a shaft bowed slightly in the form of a shallow are, each roller assembly comprising an inner member mounted on such shaft and an outer member r ounted in bearing relation to said inner member and comprising a generally cylindrical metallic element and a rubber-like element peripherally bonded to said metallic element, and a resilient protective sleeve stretched over said roller assemblies and retained in contractile engagement with the rubber-like elements of said roller assemblies.

SAMUEL L. HARLOW. JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 868,098 Kiernan Oct. 15, 1907 920,122 Farnworth May 4, 1909 1,595,544 Farrell Aug. 10, 1926 1,719,375 Isherwood July 2, 1929 2,064,993 Sperry Dec. 22, 1936 FOREIGN PATENTS Number Country Date 390,103 Great Britain Mar. 30, 1933 

